Hi Susan,
Are you backing up all the files in subdirectories too? Is it possible you are running out of space in your Windows\temp directory?
We'll see what we can do to better catch this occurrance in any event.
BTW - if you're looking for a robust, solid, on and off premise backup solution, I'd STRONGLY recommend looking at
ShadowSafe from
VitalEsafe.
It has saved Softrak's bacon 4 times in the last 12 months when people have inadvertantly deleted files that they wanted (the most common reason to need a backup copy).